Field of the Invention
The present invention relates to a developer container, a development device, a process cartridge, and an image forming apparatus.
A development device includes a developer bearing member, and the device is used to visualize an electrostatic latent image with developer. A process cartridge includes an image bearing member for bearing the developer image and a process unit acting on the image bearing member. The image bearing member and the process unit are integrated as a cartridge.
Description of the Related Art
In electrophotographic image forming apparatuses using electrophotographic imaging process, a process cartridge method has been employed. In the process cartridge method, an electrophotographic photosensitive member and a process unit acting thereon are combined into one cartridge to provide the cartridge detachable from the electrophotographic image forming apparatus body.
Such a process cartridge method enables users to perform maintenance of the apparatuses by themselves without relying on service staff, and this significantly increases the apparatus operability. For this reason, the process cartridge method has been widely used in the electrophotographic image forming apparatuses.
Process cartridges include toner, to provide the color, and developer, which consists of magnetic particles that carry the color on an outside of a magnetic developer drum. The developer allows a latent electrostatic image on the photoconductor to take up sufficient toner to give a properly colored image. In the electrophotographic image forming apparatuses employing the process cartridge method as described above, the users can replace the process cartridges by themselves. Consequently, the electrophotographic image forming apparatuses are often provided with a means for detecting toner consumption amount and notifying the users of the timing of replacement, that is, a toner remaining amount detection unit. Toner consumption amount can be based on electrical resistance properties since electrical resistance properties will change depending on the developer-toner mix.
As examples of the remaining toner amount detection unit, Japanese Patent Application Laid-Open No. 2003-248371 and Japanese Patent Application Laid-Open No. 2012-168241 discuss systems for detecting change in capacitance between a plurality of electrodes disposed in a process cartridge, and notifying a remaining toner amount. In the system in Japanese Patent Application Laid-Open No. 2003-248371, a developer bearing member is used as an input side electrode, and a capacitance detection member is used as an output side electrode. The capacitance detection member is disposed to face the developer bearing member in the development device, and capacitance is detected by applying an alternating current bias to the developer bearing member. In this structure, the process cartridge is provided with a contact member for electrically connecting the capacitance detection member and a conductive member (hereinafter, referred to as a body side remaining toner amount contact) having spring properties, the conductive member being provided in the image forming apparatus body. The application of the AC bias to the developer bearing member induces an electric current corresponding to the capacitance (remaining toner amount) between the developer bearing member and the capacitance detection member. The current value is measured, through the contact member provided at the process cartridge side, and the body side toner remaining contact, by the remaining toner amount detection unit of the image forming apparatus body and thereby the remaining toner amount can be sequentially detected.